Process and system for producing biofuels with reduced carbon intensity

N/A.

The present disclosure relates to a process and/or system for producing one or more biofuels with reduced carbon intensity, and in particular, relates to a process and/or system for producing one or more biofuels wherein biogas transported by vehicle is used to reduce the carbon intensity of the biofuel.

Concerns over depleting fossil fuel resources and the negative environmental impacts associated with the use of fossil fuels has increased interest in using biomass to produce biofuels and/or other bioproducts (e.g., plastics, fertilizers, lubricants, and/or industrial chemicals). In North America, cars often run on a gasoline/ethanol blend (e.g., E10, E15, or E85), where the ethanol is produced from corn or wheat. Interest in biofuels has been further increased as a result of government initiatives, standards, and/or programs that provide incentives for producing and/or using biofuels (e.g., the Renewable Fuel Standard Program (RFS2) in the United States, the Renewable Energy Directive (RED II) in Europe, the Renewable Transport Fuel Obligation (RTFO) in the United Kingdom, and/or the Low Carbon Fuel Standards (LCFS) in California, Oregon, or British Columbia).

Such programs, which represent an important step in curbing greenhouse gas (GHG) emissions from the transportation sector, may require oil and gas producers to comply each year using appropriate documentation (e.g., that verifies that a certain volume of renewable fuel was produced and/or that verifies that a certain GHG emission reduction was achieved). In some cases, compliance is demonstrated using fuel credits. Fuel credits (e.g., Renewable Identification Numbers (RINs) under the RFS2 or LCFS credits under California's LCFS) may be generated when biofuel is produced. For example, a RIN is a credit that may be generated for each gallon of biofuel (e.g., ethanol, biodiesel, etc.) produced, whereas each LCFS credit represents one metric ton (MT) of carbon dioxide (CO) reduced. Such fuel credits may be generated, sold, traded, and/or purchased in order to verify compliance with the applicable program.

In some cases, the biofuel must meet a predetermined GHG emission threshold in order to generate fuel credits. For example, to be a renewable fuel under the RFS2, corn ethanol should have lifecycle GHG emissions at least 20% lower than an energy-equivalent quantity of gasoline (e.g., 20% lower than the 2005 EPA average gasoline baseline of 93.08 gCOe/MJ). In low carbon-related fuel standards, biofuels may be credited according to the carbon reductions of their pathway. For example, under California's LCFS, each biofuel is given a carbon intensity (CI) score indicating their GHG emissions as grams of COequivalent per megajoule of fuel, and fuel credits are generated based on a comparison of their emissions reductions to a target or standard that may decrease each year (e.g., in 2019, ethanol is compared to the gasoline average CI of 93.23 gCOe/MJ), where lower CIs generate proportionally more credits.

The lifecycle GHG emissions and CI of a biofuel such as ethanol can vary depending upon the feedstock and fuel production process. In a non-limiting example, corn ethanol having a CI of 70 gCOe/MJ, may have about 20 g/MJ associated with land use change, about 29 g/MJ associated with agriculture (e.g., including the production of fertilizer and soil amendments), about 27 g/MJ associated with biorefining, about 6 g/MJ associated with miscellaneous items such as transporting the feedstock and/or ethanol, and about −12 g/MJ associated with the production of co-products (e.g., distiller's grain and solubles (DGS)). Some factors that affect the CI of ethanol include the feedstock (e.g., corn or sorghum), the type of refining process used (e.g., dry or wet milling), the process fuel used (e.g., natural gas, coal, or biomass), the co-products produced (e.g., wet or dry DGS), and the quantity of electricity purchased from the grid and/or the grid location. For example, since producing dry DGS (DDGS) can require a relatively high amount of energy to dry the DGS, producing wet DGS (WDGS) can typically produce ethanol with a lower CI.

Some approaches proposed to reduce the lifecycle GHG emissions or CI of biofuels, such as ethanol, include using solar power, using biogas, and/or using membrane dehydration. For example, biogas can be produced by an anaerobic digester used to treat waste streams in the ethanol production process (e.g., evaporated condensate, dryer/scrubber streams, thin stillage). Unfortunately, biogas production from these streams may be insufficient to supply the natural gas and/or electricity needs of the process. It has been also proposed to collect biogas produced at a dairy farm and transport it by pipeline to the plant. Unfortunately, this approach may be limited to specific ethanol plants (e.g., located geographically close to the dairy farm) and may also be insufficient to supply the natural gas and/or electricity needs of the process.

The present disclosure describes a method and/or system for producing one or more fuels (e.g., a biofuel) wherein biogas is transported to the fuel production plant by vehicle (i.e., in a mobile vessel) and is used to produce heat and/or power for producing the fuel.

The biogas, which may be transported as raw biogas, partially purified biogas, or renewable natural gas (RNG), may be compressed to a pressure of at least 1000 psig (6.89 MPa), at least 1500 psig (10.34 MPa), or at least 2000 psig (13.79 MPa), for transport. While compressing biogas to pressures of at least 2000 psig (13.79 MPa) is an energy intensive process that can increase the energy usage of the process and thus may increase the CI of the biofuel (e.g., relative to an analogous case wherein the biogas is transported in a low pressure pipeline and/or is minimally compressed), various embodiments described herein exploit the compressed state of the biogas to reduce net electricity and/or methane usage (i.e., relative to an analogous case wherein the compressed state of the biogas is not exploited) of the fuel production process.

In accordance with one aspect of the instant invention there is provided a process for producing a biofuel comprising: (a) providing biogas from one or more biogas sources, said biogas comprising methane and provided in one or more mobile vessels, each mobile vessel pressurized to at least 2000 psig (13.79 MPa); (b) removing and depressurizing biogas from each of the one or more mobile vessels; (c) generating heat, power, or a combination thereof, by combusting a gas comprising methane from the biogas removed and depressurized from the one or more mobile vessels; and (d) producing a biofuel or biofuel intermediate in a production process that includes treating a feedstock, said production process including the use of the heat, power, or a combination thereof, generated in step (c), wherein a quantity of biogas used to produce the heat, power, or combination thereof used in step (d) is sufficient to reduce a carbon intensity of the biofuel or biofuel intermediate by at least 5 gCOe/MJ, and wherein a change in pressure provided by the depressurizing in step (b) is used to provide work for the production process, cooling for the production process, increased pressure for the production process, or a combination thereof.

In accordance with one aspect of the instant invention there is provided a process for producing one or more biofuels comprising: (a) treating a feedstock to produce one or more sugars; (b) adding a fermentation organism to a mixture comprising the one or more sugars and fermenting the one or more sugars to produce ethanol; (c) recovering the ethanol; (d) removing and depressurizing biogas from one or more mobile vessels pressurized to at least 2000 psig (13.79 MPa), said removed and depressurized biogas comprising methane; (e) generating heat, power, or a combination thereof from at least a portion of the methane; and (f) using the heat, power, or combination thereof in step (a), step (b), step (c), or a combination thereof, thereby reducing a carbon intensity of the ethanol, wherein a change in pressure provided by the depressurizing in step (d) is used to provide (i) work for step (a), step (b), step (c), or a combination thereof, (ii) cooling for step (a), step (b), step (c), or a combination thereof, (iii) increased pressure for step (a), step (b), step (c), or a combination thereof, or (iv) any combination thereof.

In accordance with one aspect of the instant invention there is provided a process for producing one or more biofuels comprising: (a) treating a feedstock to produce one or more sugars; (b) adding a fermentation organism to a mixture comprising the one or more sugars and fermenting the one or more sugars to produce ethanol; (c) recovering the ethanol; (d) removing and depressurizing biogas from one or more mobile vessels having a pressure of at least 2000 psig (13.79 MPa), said removed and depressurized biogas comprising methane; (e) generating heat, power, or a combination thereof from at least some of the methane; (f) using the heat, power, or combination thereof in step (a), step (b), step (c), or a combination thereof, thereby reducing a carbon intensity of the ethanol, wherein said depressurizing comprises providing a pressure drop that cools the removed biogas, and wherein the process comprises providing heat transfer between the cooled biogas and a heat transfer medium and providing cooling for the process with the heat transfer medium.

In accordance with one aspect of the instant invention there is provided a process for producing one or more biofuels comprising: (a) treating a feedstock to produce one or more sugars; (b) adding a fermentation organism to a mixture comprising the one or more sugars and fermenting the one or more sugars to produce ethanol; (c) recovering the ethanol; (d) removing and depressurizing biogas from one or more mobile vessels having a pressure of at least 2000 psig (13.79 MPa), said removed and depressurized biogas comprising methane; (e) generating heat, power, or a combination thereof from at least some of the methane; and (f) using the heat, power, or combination thereof in step (a), step (b), step (c), or a combination thereof, thereby reducing a carbon intensity of the ethanol, wherein said depressurizing the biogas from the one or more mobile vessels comprises providing biogas at a pressure of at least 200 psig (1.38 MPa), wherein generating heat, power, or a combination thereof from at least some of the methane comprises feeding the biogas or a gas derived from the biogas into a gas turbine at a pressure greater than 200 psig (1.38 MPa), and wherein the process is substantially free of significant compression of the biogas removed from the one or more mobile vessels or gas derived from the biogas before being fed to the gas turbine.

Certain exemplary embodiments of the invention now will be described in more detail, with reference to the drawings, in which like features are identified by like reference numerals. The invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. The terminology used herein is for the purpose of describing certain embodiments only and is not intended to be limiting of the invention. For example, as used herein, the singular forms “a,” “an,” and “the” may include plural references unless the context clearly dictates otherwise. The terms “comprises”, “comprising”, “including”, and/or “includes”, as used herein, are intended to mean “including but not limited to.” The term “and/or”, as used herein, is intended to refer to either or both of the elements so conjoined. The phrase “at least one” in reference to a list of one or more elements, is intended to refer to at least one element selected from any one or more of the elements in the list of elements, but not necessarily including at least one of each and every element specifically listed within the list of elements. Thus, as a non-limiting example, the phrase “at least one of A and B” may refer to at least one A with no B present, at least one B with no A present, or at least one A and at least one B in combination. In the context of describing the combining of components by the “addition” or “adding” of one component to another, or the separating of components by the “removal” or “removing” of one component from another, those skilled in the art will understand that the order of addition/removal is not critical (unless stated otherwise). The terms “remove”, “removing”, and “removal”, with reference to one or more impurities, contaminants, and/or constituents of biogas, includes partial removal. The terms “cause” or “causing”, as used herein, may include arranging or bringing about a specific result (e.g., a withdrawal of a gas), either directly or indirectly, or to play a role in a series of activities through commercial arrangements such as a written agreement, verbal agreement, or contract. The term “associated with”, as used herein with reference to two elements (e.g., a fuel credit associated with the transportation fuel), is intended to refer to the two elements being connected with each other, linked to each other, related in some way, dependent upon each other in some way, and/or in some relationship with each other. The terms “first”, “second”, etc., may be used to distinguish one element from another, and these elements should not be limited by these terms. The term “plurality”, as used herein, refers to two or more. Unless defined otherwise, all technical and scientific terms used herein have the same meanings as commonly understood by one of ordinary skill in the art.

Referring to, there is shown an embodiment of the invention, wherein a process for producing one or more biofuels includes the steps of producing a biofuel from one or more feedstocks, removing biogas from one or more mobile vessels, and using the removed biogas to provide heat (e.g., steam) and/or power (e.g., electricity)for the fuel production process. Advantageously, since at least a portion of the heat and/or power used for the fuel production processis produced from biogas, the carbon intensity (CI) of the biofuel can be reduced (i.e., relative to the case where that portion of the heat and/or power was produced from fossil fuels). In one embodiment, the biogas removed from the one or more mobile vesselsis raw biogas, partially purified biogas, and/or RNG. In one embodiment, the biogas removed from the one or more mobile vesselsis raw biogas and/or partially purified biogas.

While using biogas to reduce the CI of a biofuel is known, the approaches proposed typically produce raw biogas on site (e.g., with one or more anaerobic digesters) or transport raw biogas over short distances by pipeline (i.e., to the site). Such approaches are compatible with the relatively low economic value of raw biogas (i.e., relative to natural gas) and with the fact that raw biogas typically has a relatively high COcontent, which can make it more challenging to transport (e.g., economically and/or technically). In contrast, in the embodiment described in, the biogas is provided in one or more mobile vessels, and thus can be transported by vehicle (e.g., truck). In one embodiment, the biogas removed from the one or more mobile vesselsis pressurized to at least 1000 psig (6.89 MPa), at least 1500 psig (10.34 MPa), or at least 2000 psig (13.79 MPa). In one embodiment, removing the biogas from the one or more mobile vessels includes depressurizing the biogas. In one embodiment, the biogas in the one or more mobile vessels is pressurized to at least 2000 psig (13.79 MPa), and the process includes depressurizing the biogas using a depressurization method that reduces utility requirements (i.e., electricity and/or natural gas) of the production processper unit of biofuel produced, relative to an analogous process where the depressurization method is not used to reduce utility requirements. In one embodiment, the biogas in the one or more mobile vessels is pressurized to at least 2000 psig (13.79 MPa), and the process includes depressurizing the biogas using a depressurization method that reduces the process energy requirements per unit of biofuel. In general, pressurizing the biogas to at least 2000 psig (13.79 MPa) in the one or more mobile vessels requires significant energy. The energy introduced by the pressurization can be stored in and/or recovered from the high-pressure gas and used in the fuel production process. In one embodiment, at least a portion of the latent energy of the compressed biogas is harnessed to provide work (e.g., electricity or to drive rotary equipment), to provide cooling, and/or to provide increased pressure for the fuel production process. In one embodiment, removing the biogas from the one or more mobile vessels decreases the enthalpy of the biogas, and the process includes recovering enthalpy from the decompression for use in the process (e.g., by providing work and/or cooling). In one embodiment, removing the biogas from the one or more mobile vessels decreases the enthalpy of the biogas, and depressurization is controlled such that the enthalpy of the depressurized biogas used to produce the heat and/or power is higher than the enthalpy of an equivalent amount of natural gas (i.e., in energy content) provided from a commercial distribution system connected to the fuel production facility (e.g., at a pressure less than 30 psig (0.21 MPa), less than 20 psig (0.14 MPa), or less than 10 psig (0.07 MPa)). In one embodiment, removing the biogas from the one or more mobile vessels includes providing a change in pressure used to provide work, cooling, and/or increased pressure that is used in the fuel production process.

Referring to, there is shown an embodiment of the invention, wherein a process for producing one or more biofuels includes the steps of producing a biofuel from one or more feedstocks, removing and depressurizing biogas from one or more mobile vessels, and using the biogas removed from the one or more mobile vessels to provide heat (e.g., steam) and/or power (e.g., electricity)for the fuel production process. Advantageously, since at least a portion of the heat and/or power used for the fuel production processis produced from biogas, the lifecycle GHG emissions of the biofuel can be reduced (i.e., relative to the case where that portion of the heat and/or power was produced from fossil fuels). In this embodiment, the biogas that is removed from the one or more mobile vesselsis raw biogas, partially purified biogas, or RNG, and is depressurized using a depressurization method wherein a temperature of the removed biogas is reduced (e.g., as the biogas is expanded it is cooled as a result of the Joule Thomson effect). In one embodiment, the temperature drop provided by the pressure change is used to provide cooling for the fuel production process. In one embodiment, the process includes providing heat transfer between the cooled biogas and a heat transfer medium, and using the heat transfer medium to provide coolingin the fuel production process, thereby reducing the process energy requirements per unit of biofuel (e.g., less electricity is required for process chilling since cold is provided from the depressurization). In one embodiment, the lower temperature provided by the depressurization is used to cool a circulating fluid that provides cooling within the fuel production process. One approach to providing cooling in fuel production processes (e.g., oil refining, corn ethanol, etc.) is to use a cooling tower, wherein circulating water warmed by the process is cooled as it cascades over baffles (or fill), which promotes evaporation. While widely used, cooling towers unfortunately can increase water usage of the fuel production process. However, by using the temperature drop provided by depressurization, water usage of the fuel production process does not significantly increase as a result of the cooling process. Moreover, it is not limited by ambient temperatures. Advantageously, using the temperature drop provided by depressurization to decrease the temperature of a circulating water (e.g., warmed by the fuel production process) also increases the temperature of the removed biogas. Since biogas provided at relatively low temperatures (e.g., below about −20° C., below about −25° C., below about −40° C., or below about −50° C.) can need to be reheated before further processing and/or combustion (e.g., to reduce risks of line freezing and/or damage to equipment), this can reduce costs associated with heating the cooled biogas.

Referring to, there is shown an embodiment of the invention, wherein a process for producing one or more biofuels includes the steps of producing a biofuel from one or more feedstocks, removing and depressurizing biogas from one or more mobile vessels, and using the biogas removed from the one or more mobile vessels to provide heat (e.g., steam) and/or power (e.g., electricity)for the fuel production process. Advantageously, since at least a portion of the heat and/or power used for the production processis produced from biogas, the lifecycle GHG emissions of the biofuel can be reduced (i.e., relative to the case where that portion of the heat and/or power was produced from fossil fuels). In this embodiment, the biogas that is removed from the one or more mobile vesselsis raw biogas, partially purified biogas, or RNG, and is depressurized using a depressurization method that produces work for the fuel production process (e.g., using a turboexpander). In one embodiment, the change in pressure from the depressurization is sufficient to drive the shaft of a turboexpander that is coupled to a generator (e.g., for generating electricity) or another piece of equipment (e.g., a compressor, blower, etc.). In one embodiment, the process includes generating electricity using the turboexpander, and using the electricity generated in the production process(e.g., to drive equipment in the process), thereby reducing energy requirements per unit of biofuel. In one embodiment, the process includes using the turboexpanderto drive one or more pieces of equipment (e.g., blower, pump, milling equipment, etc.), thereby reducing the energy requirements per unit of biofuel. In one embodiment, the biogas is removed from the one or more mobile vessels such that the pressure of the biogas removed from the one or more vessels is substantially constant (and relatively high) as it is fed to the turboexpander (e.g., using a positive displacement method wherein the biogas is displaced from the mobile vessel(s) using a liquid or piston).

Referring to, there is shown an embodiment of the invention, wherein a process for producing one or more biofuels includes the steps of producing a biofuel from one or more feedstocks, removing and depressurizing biogas from one or more mobile vessels, and using the biogas removed from the one or more mobile vessels to provide heat (e.g., steam) and/or power (e.g., electricity)for the fuel production process. Advantageously, since at least a portion of the heat and/or power used for the fuel production processis produced from biogas, the lifecycle GHG emissions of the biofuel can be reduced (i.e., relative to the case where that portion of the heat and/or power was produced from fossil fuels). In this embodiment, the biogas is raw biogas, partially purified biogas, or RNG, and removing and depressurizing the biogasincludes depressurizing the biogas from a first pressure to a second pressure P, where the second pressure P is at least 100 psig (0.69 MPa). For example, in one embodiment, the second pressure P is at least 150 psig (1.03 MPa), at least 200 psig (1.38 MPa), at least 300 psig (2.07 MPa), 400 psig (2.76 MPa), 500 psig (3.45 MPa), 600 psig (4.14 MPa), 700 psig (4.83 MPa), 800 psig (5.52 MPa), 900 psig (6.20 MPa), 1000 psig (6.89 MPa), 1100 psig (7.58 MPa), or at least 1200 psig (8.27 MPa). Biogas (i.e., raw, partially purified, or fully upgraded) at the second pressure P is combusted to produce heat and/or power. In some cases, combustion units used to produce heat and/or power can function more efficiently with high fuel input pressures. For example, a gas turbine may operate with fuel pressures of about 180 psig (1.24 MPa) or higher (e.g., between 580 to 1020 psig), and thus may require that the fuel be fed to an upstream compressor. In the embodiment illustrated in, the relatively high pressure of the biogas in the one or more mobile vessels is exploited to avoid, or reduce, compression of the biogas before it is combusted. For example, in one embodiment, the one or more mobile vessels are only depressurized to a pressure that corresponds approximately to the fuel input pressure recommended for the combustion unit, thereby reducing compression requirements for the combustion (e.g., relative to if the biogas was transported by pipeline at a pressure under 80 psig (0.55 MPa)), thereby reducing the process energy requirements per unit of biofuel.

Referring to, there is shown an embodiment of the invention, wherein a process for producing one or more biofuels includes the steps of producing a biofuel from one or more feedstocks, removing and depressurizing biogas from one or more mobile vessels, and using the biogas removed from the one or more mobile vessels to provide heat (e.g., steam) and/or power (e.g., electricity)for the fuel production process. Advantageously, since at least a portion of the heat and/or power used for the fuel production processis produced from biogas, the lifecycle GHG emissions of the biofuel can be reduced (i.e., relative to the case where that portion of the heat and/or power was produced from fossil fuels). In this embodiment, the biogas is raw biogas and/or partially purified biogas, and removing and depressurizing the biogasincludes depressurizing the biogas from a first pressure to a second pressure P, where the second pressure is at least 100 psig (0.69 MPa). For example, in one embodiment, the second pressure is at least 200 psig (1.38 MPa), at least 300 psig (2.07 MPa), 400 psig (2.76 MPa), 500 psig (3.45 MPa), 600 psig (4.14 MPa), 700 psig (4.83 MPa), 800 psig (5.52 MPa), 900 psig (6.20 MPa), 1000 psig (6.89 MPa), 1100 psig (7.58 MPa), or at least 1200 psig (8.27 MPa). Biogas (i.e., raw or partially purified) at the second pressure P is fed to a biogas upgrading system wherein it is at least partially upgraded, and the at least partially upgraded biogas is then combusted to generate heat and/or electricity. In this embodiment, the biogas upgrading system requires an input gas feed that is at an elevated pressure (i.e., at least 200 psig) in order to function efficiently. In one embodiment, the upgraded biogas is then depressurized and fed to the combustion unit. In one embodiment, the biogas upgrading system is configured to operate substantially at this elevated pressure P and to provide an upgraded biogas at a pressure that is at least 200 psig, at least 300 psig (2.07 MPa), at least 400 psig (400 psig), at least 500 psig (3.45 MPa), at least 600 psig, at least 700 psig (4.83 MPa), at least 800 psig (5.52 MPa), at least 900 psig (6.20 MPa), or at least 1000 psig (6.89 MPa), without substantial compression. By reducing compression requirements after the biogas has been transported to the fuel production facility, energy requirements per unit of biofuel are reduced.

In each of these embodiments, the relatively high pressure of the biogas in the one or more mobile vessels (e.g., raw, partially purified, and/or RNG) can be exploited to reduce energy requirements of the fuel production process (e.g., reduce utilities), thereby recovering some of the energy used to compress the biogas when filling the one or more mobile vessels. This offset may be particularly important when the biogas is provided to reduce the lifecycle GHG emissions of the biofuel. For example, if the carbon emissions associated with biogas production (e.g., including those for compressing and transporting the biogas) is higher than the GHG reductions achieved by displacing natural gas, then the lifecycle GHG emissions of the product may not be reduced.

In each of these embodiments, at least some of the biogas for the production processis provided in one or more mobile vessels. Accordingly, at least some of the biogas may be provided from one or more biogas sources that are not physically connected by pipeline to the fuel production facility (although in some embodiments the fuel production facility may also include and/or be connected to one or more sources of biogas). While compressing biogas and transporting it in a mobile vessel may result in additional GHG emissions (e.g., relative to transporting it by pipeline), the net GHG emissions for the biofuel can be reduced with the selection of suitable amounts and types of biogas (e.g., different biogas sources). For example, while upgraded landfill gas may have a carbon intensity (CI) of about 40-50 gCOe/MJ, biogas produced from manure is typically lower (e.g., dairy manure may have CI of about −270 gCOe/MJ, while swine manure may have a CI that is about −350 gCOe/MJ). Providing a delivery system that includes transporting biogas in one or more mobile vessels allows biogas to be collected from multiple farms (e.g., dairy or swine) that otherwise could be emitted to the atmosphere and/or flared.

In one embodiment, the biogas removed from the one or mobile vessels is provided using a delivery system wherein biogas from a plurality of biogas sources is transported to a receiving station(e.g., as illustrated in). More specifically, biogas from each biogas source,,, is compressed in a respective mobile vessel and is transported directly to the receiving station, where it can be removed and depressurized, and used to provide heat and/or power for the fuel production process. In one embodiment, the receiving station includes connecting means (e.g., high pressure piping, tubing, flexible hose, manifold(s), switching valves, couplings, etc.) for connecting to the one or more mobile vessels. In one embodiment, the receiving station includes a plurality of docks, each of which is designed to accommodate a different mobile vessel or truck supporting one or more mobile vessels. In one embodiment, the receiving station includes a plurality of docking stations, each of which can accommodate a trailer, skid, or shipping container. In one embodiment, the receiving station includes a pressure let down system. In one embodiment, the receiving station is located at the fuel production facility. In one embodiment, the receiving station is located at a processing site connected to a plurality of farms by pipeline.

In one embodiment, the delivery system includes one or more trucks fueled by biogas, partially purified biogas, or RNG. In one embodiment, the delivery system includes one or more trucks fueled by bio-CNG or bio-LNG.

In one embodiment, the biogas from each biogas source is transported as raw biogas. In one embodiment, the biogas from each biogas source is transported as partially purified biogas. In one embodiment, the biogas from each biogas source is transported as RNG. In one embodiment, the biogas provided in different mobile vessels has different purities (e.g., different methane contents). In one embodiment, the biogas from one biogas source is transported as raw biogas, while biogas from another biogas source is transported as partially purified biogas or RNG.

In one embodiment, the fuel production process produces a single biofuel or biofuel intermediate (e.g. ethanol, DME, diesel having renewable content, methanol, etc.). In one embodiment, the fuel production process produces a plurality of biofuels and/or fuel intermediates. In one embodiment, the fuel production process produces ethanol and RNG. In one embodiment, the fuel production process produces at least one biofuel or biofuel intermediate other than RNG.

Biogas Production

For purposes herein, the term “biogas”, which refers to a gas mixture that contains methane produced from the anaerobic digestion of organic matter, encompasses raw biogas, partially purified biogas, and renewable natural gas (RNG), unless otherwise specified. Raw biogas refers to biogas before it is treated to remove any chemical components (e.g., CO, HS, HO, N, NH, H, CO, O, VOCs, and/or siloxanes). The term “partially purified biogas” refers to biogas that has been treated to remove non-methane components (e.g., CO, HS, HO, N, NH, H, CO, O, VOCs, and/or siloxanes), but requires further purification in order to meet pipeline specifications (e.g., it may contain one or more non-methane components in an amount that causes it to fall short of meeting natural gas pipeline standards or specifications). The term “renewable natural gas” or “RNG” refers to biogas that has been upgraded to meet or exceed applicable natural gas pipeline quality standards and/or specifications, meet or exceed applicable quality specifications for vehicle use (e.g., CNG specifications), and/or that qualifies as RNG under applicable regulations. Pipeline specifications include specifications required for biogas for injection into a natural gas commercial distribution system. Pipeline quality standards or specifications may vary by region and/or country in terms of value and units. For example, pipelines standards may require the RNG to have a CHlevel that is at least 95% or have a heating value of at least 950 BTU/scf.

In general, the biogas provided in the one or more mobile vessels may include biogas from any suitable source. For example, the biogas may be obtained from a landfill and/or from one or more anaerobic digesters. In embodiments where the biogas is obtained from one or more anaerobic digesters, the digesters may be connected in series and/or in parallel, may be single-stage or multi-stage digestion systems, and/or may be designed and/or operated in a number of configurations including batch or continuous, mesophilic or thermophilic temperature ranges, and low, medium, or high rates. In addition, in embodiments where the biogas is obtained from one or more anaerobic digesters, the digesters may be used for manure or other farm waste, for wastewater treatment, for treating industrial waste, and/or for treating wastewater, wastes, and/or residues from an ethanol process. In one embodiment, the biogas is sources from one or more anaerobic digesters fed manure. In one embodiment, the biogas is sourced from one or more manure-fed anaerobic digesters at a dairy farm. In one embodiment, the biogas is sourced from one or more manure-fed anaerobic digesters at a swine farm. In one embodiment, the biogas is sourced from a landfill site. In one embodiment, the biogas is sourced from a wastewater treatment plant (WWTP). In one embodiment, the biogas is sourced from one or more anaerobic digesters processing manure and/or from a landfill.

Raw biogas may, for example, have a methane (CH) content between about 35% and 75% (e.g., average of about 60%) and a carbon dioxide (CO) content between about 15% and 65% (e.g., average of about 35%), depending on the source. For example, without being limiting, biogas from anaerobic digesters fed agricultural waste may have a methane content between about 50% and 75%, whereas biogas from a landfill site may have a methane content between about 25% and 65%. In one embodiment, the raw biogas has a methane content between about 25% and 75% and a carbon dioxide content between about 15% and 65%, and the carbon dioxide and methane make up at least 75% of the biogas by volume.

In one embodiment, each biogas source (e.g., based on landfill or anaerobic digester) produces raw biogas at a rate less than 6000 SCFM (standard cubic feet per minute). In one embodiment, the biogas source produces raw biogas at a rate less than 5000 SCFM. In one embodiment, the biogas source produces raw biogas at a rate between 100 and 3000 SCFM. In one embodiment, the biogas source produces raw biogas at a rate between 1000 and 3000 SCFM. In one embodiment, the biogas source produces raw biogas at a rate between 1500 and 3000 SCFM.

The percentages used to quantify gas composition and/or a specific gas content, as used herein, are expressed as mol %, unless otherwise specified.

Partial Purification and/or Biogas Upgrading

In general, the biogas provided from each biogas source may be purified before and/or after transport by mobile vessel.

In one embodiment, the biogas from each source is partially purified at a processing site at or close to the corresponding biogas source,,(e.g., before transport in the mobile vessel). In one embodiment, the partial purification removes HO, HS, and/or COfrom the raw biogas to provide partially purified biogas having a HO content, HS content, and/or COcontent that is less than that of the raw biogas. Optionally, one or more other non-methane components are removed.

In embodiments where the biogas is partially purified at each processing site, the partial purification does not produce a gas that meets applicable quality specifications for injection into the natural gas distribution system (e.g., pipeline standards) and/or is suitable for use in the transportation sector, but rather, requires further purification in order to qualify as RNG under applicable regulations. For example, in one embodiment, the partially purified biogas has a non-methane content of at least 20%, at least 15%, at least 12%, at least 10%, at least 8%, at least 6%, or at least 5%. In one embodiment, the partially purified biogas has an inert content (e.g., CO, N, helium, argon, neon) that is greater than 10%.

In one embodiment, the partially purified biogas has a COcontent less than 10%, less than 9%, less than 8%, less than 7%, less than 6%, or less than 5%. In one embodiment, the partially purified biogas has a COcontent between about 4% and 8%, between about 4% and 9%, or between about 4% and 10%. In one embodiment, the partially purified biogas has a CHcontent between about 50% and about 93%. In one embodiment, the partially purified biogas has a CHcontent between about 50% and about 90% and an Ncontent between about 10% and 20%. In one embodiment, the partially purified biogas has a CHcontent between about 80% and about 90% and an Ncontent between about 10% and 20%. In one embodiment, the partially purified biogas has a CHcontent between about 72% and about 90%, a COcontent between about 0 and 8%, and an Ncontent between about 5% and 20%. In one embodiment, the partially purified biogas has a combined CHand Ncontent that is greater than 98%, where the Ncontent is at least 5%. In one embodiment, the partially purified biogas has a combined CHand Ncontent that is greater than 98%, and a COcontent that is less than 1%. In one embodiment, the partially purified biogas has a combined CHand Ncontent that is greater than 98%, where the Ncontent is at least 5%, and wherein the COcontent is less than 200, 100, 50, or 30 ppm.

In one embodiment, the partially purified biogas has a non-methane content that is at least 50%, at least 55%, at least 60%, at least 65%, or at least 70%. In one embodiment, the partially purified biogas has a non-methane content that is greater than 60%. In one embodiment, the partially purified biogas has a non-methane content between 50% and 60%. In one embodiment, less than 5%, less than 10%, less than 15%, or less than 20% of the COpresent in the raw biogas is removed in the partial purification.

In one embodiment, the partial purification of the raw biogas is provided using a stationary purification system (e.g., installed at the processing site). Using a stationary purification system advantageously allows the partial purification system to be readily available on-site to at least partially purify the raw biogas as it is produced. Moreover, since the purification system is stationary it can be designed and/or selected in dependence upon the average composition of the raw biogas from that particular source. Furthermore, since the purification system remains on-site (e.g., is not transported with the vessels) more partially purified biogas may be transported. For purposes herein, the term “stationary” as used with reference to a purification system, refers to the purification system not moving from the pre-processing site or facility at which it is used (although it may move within the processing site or facility).

In one embodiment, at least part of the partial purification is achieved using a stationary purification system based on any suitable method/technology, or combination of methods/technologies, in one or more stages, as known in the art. For example, HO may be removed using a standard biogas dehumidifier, whereas HS may be removed using a commercial HS removal unit (e.g., based on activated carbon, molecular sieve, iron sponge, water scrubbing, NaOH washing, and/or biofilter or biotrickling filter technologies). In one embodiment, the partial purification system includes a dehumidifier, a scrubber, a membrane unit, a solvent extraction unit, a pressure swing adsorption unit, and/or a cryogenic unit.

In one embodiment, the partial purification is essentially a cleaning or pre-cleaning stage that does not significantly remove COor N. For example, in one embodiment, the partial purification removes HO and/or HS, but does not significantly remove COor N.

In one embodiment, the partial purification removes HO. Raw biogas may be fully saturated with water vapour and/or may have a water content of about 7% (at 40° C.). Removing HO is advantageous since moisture can condense into water or ice when passing from high to low pressure systems, which may cause corrosion, may result in clogging, and/or may interfere with gas flow and pressure measurements (e.g., causing system control problems). In addition, the presence of water may cause hydrates to form. In one embodiment, the partial purification removes more than 90%, 92%, 94%, 96%, or 98% of the HO present in the raw biogas. In one embodiment, the partial purification removes more than 99% of the HO present in the raw biogas. In one embodiment, the partial purification removes sufficient HO from the raw biogas that the HO content of partially purified biogas meets or exceeds the HO content specifications for RNG. In one embodiment, the partial purificationdoes not remove HO. In one embodiment, the partial purification removes sufficient moisture to provide the partially purified biogas with an HO concentration of less than 0.4 g/mof biogas. In one embodiment, the partial purification removes sufficient moisture to provide the partially purified biogas with an HO concentration of less than 0.2 g/mof biogas. In one embodiment, the partial purification includes an HO removal stage that uses refrigeration techniques or desiccant drying. In one embodiment, the partial purification includes multi-stages of HO removal (e.g., first stage of HO removal followed by a second stage of HO removal), which may or may not be consecutive.

In one embodiment, the partial purification removes HS. Raw biogas may have an HS concentration between about 0 and about 6700 ppm(v) (e.g., 0-10,000 mg/m). For example, without being limiting, biogas derived from agricultural waste may have an HS concentration between 0-4000 ppm(v), whereas biogas from a landfill may have an HS concentration between 0 and 1000 ppm(v). HS is both poisonous and corrosive, and can damage piping, equipment, and instrumentation. HS can be reactive with many metals, and the reactivity can be higher at higher concentration and pressure, and/or in the presence of water. In one embodiment, the partial purification removes more than 90%, 92%, 94%, 96%, or 98% of the HS present in the raw biogas. In one embodiment, the partial purification removes more than 99% of the HS present in the raw biogas. In one embodiment, the partial purification removes sufficient HS from the raw biogas that the HS content of partially purified biogas meets or exceeds the HS content specifications for RNG. In one embodiment, the partial purification removes sufficient HS from the raw biogas that the HS content of partially purified biogas is safer to transport but requires additional HS removal to meet RNG standards. In one embodiment, the partial purification does not remove HS. In one embodiment, the partial purification removes sufficient HS from the raw biogas that the HS concentration of partially purified biogas is less than 200 ppm(v). In one embodiment, the partial purification removes sufficient HS from the raw biogas that the HS concentration of partially purified biogas is less than 100 ppm(v). In one embodiment, the partial purification removes sufficient HS from the raw biogas that the HS concentration of partially purified biogas is between 20 ppm(v) and 50 ppm(v). In one embodiment, the partial purification removes sufficient HS from the raw biogas that the HS concentration of partially purified biogas is less than 50, 40, 30, 20, or 10 ppm(v). In one embodiment, the partial purification removes sufficient HS from the raw biogas that the HS concentration of partially purified biogas is less than about 6 ppm(v). In one embodiment, the partial purification includes a first stage of HS removal (e.g., biological) followed by second stage of HS removal (e.g., an adsorption bed), which may or may not be consecutive.

In one embodiment, the partial purification removes HO and HS. Contaminants such as O, NH, VOCs, siloxanes, and/or particulates are optionally removed, although this is not necessary. Although the fuel production processmay include HO and/or HS removal (e.g., to protect the combustion system), it can be advantageous to remove HO and/or HS prior to collection and/or transport. For example, transporting gas with HS creates the risk that in the event of a leak or accident, HS leaks out, thereby creating toxic gas and safety issues. This risk is eliminated or reduced when the partial purification includes HS removal.

In addition, since HS, and in particular the combination of HO and HS, can cause corrosion problems, removing the HO and/or HS can reduce equipment maintenance costs, and provide flexibility on construction materials for mobile vessels. Furthermore, removing HS may improve the CO/CHseparation if present during the partial purification. Removing water may reduce the risk of hydrate formation.

In one embodiment, the partial purification removes O. Removing Omay be particularly advantageous prior to compression and transport.

In one embodiment, the partial purification removes CO. In one embodiment, the partial purification removes COand/or N. Contaminants such as HO, HS, O, NH, VOCs, siloxanes, and/or particulates are optionally removed. For example, some COremoval technologies also remove HS. Even removing half of the COpresent in biogas can significantly reduce the amount of gas that needs to be compressed and/or transported. For example, transporting partially purified biogas, particularly when COhas been removed, is generally more efficient (e.g., in terms of both costs and GHG emission reductions) than transporting raw biogas. In addition, the COin raw biogas can make it more challenging (e.g., there can be phase change issues when COis compressed or depressurized) and/or less energy efficient to compress relative to pure CH.

In one embodiment, the partial purification removes more than 90%, 92%, 94%, 96%, or 98% of the COpresent in the raw biogas. In one embodiment, the partial purification removes more than 20%, 30%, 40% or 50% of the COpresent in the raw biogas. In one embodiment, the partial purification removes between about 5% and 20% of the COpresent in the raw biogas. In one embodiment, the partial purification removes less than 5% of the COpresent in the raw biogas. In one embodiment, the partial purification does not substantially remove CO. In one embodiment, no more than 75% of the COis removed.

In one embodiment, the partial purification removes sufficient COto increase the heating value of the biogas by at least 50 BTU/scf, at least 100 BTU/scf, at least 150 BTU/scf, at least 200 BTU/scf, or at least 250 BTU/scf. For example, in one embodiment, the partial purification increases the heating value of the biogas (e.g., which may be about 350-500 BTU/scf) to at least 600 BTU/scf, at least 700 BTU/scf, or at least 800 BTU/scf, but retains sufficient COand/or Nsuch that the heating value does not exceed 900 BTU/scf, 925 BTU/scf, or 950 BTU/scf. The term “heating value”, as used herein, refers to the higher heating value (HHV), unless otherwise specified.

In one embodiment, the partial purification removes sufficient COfrom the raw biogas that the COcontent of partially purified biogas is less than 25%. In one embodiment, the partial purification removes sufficient COfrom the raw biogas that the COcontent of partially purified biogas is less than 20%, 15%, 10%, or 8%. In one embodiment, the partial purification removes sufficient COfrom the raw biogas that the COcontent of partially purified biogas is less than 5%. In one embodiment, the partial purification removes sufficient COfrom the raw biogas that the COcontent of partially purified biogas is less than 4%.